Tread block core for endless tracks and the like



March 6, 1945. E. L. ALLEN ETAL TREAD BLOCK CORES FORFNDLESS TRACKS AND THE LIKE Original Filed Jan. 14, 1942 lA/l/'A/I'U/RS fowl/v L. ALLEN 4 #42040 B. Musrsl? BY A770 FIVE .5

Patented Mar. 6, 1945 UNITED STATES PATENT OFFICE: I 2,371,015 I c mean BLOCK cons roe ENDLESS TRACKS AND THE LIKE I Edwin L. Allen, Cleveland Heights, and Harold B.

Muster, Avon Lake, Ohio, assignors to Rudolph t I. Sch'onitzer; Shaker Heights, Ohio 1 "Original application January 14, 1942, Serial No.

Divided and this application Februe ary 1, 1944, .Serial No. 520,600

3 Claims. (o1. 305-) This invention relates to endless tracks for vehicles such as tanks, tractors and the like. More particularly, the present invention relates to improvements in the re-jenforcing cores of rubber tread blocks .for such tracks.

The type of tread block core with which the present invention is concerned is one having generally cylindrical passageways adjacent, and substantially parallel with, the'front and rear core edges for the extension therethrough of cross rodsby means of which a set of tread blocks, containing cores of the characterhereinvolved, may be connected to form an endless track, the laterally projecting end portions of the cross rods being provided, on each side of -the track,with suitable means-(not, here involved and not. here shown) which not only -maintain the tread blocks in assembled track-forming. relationship but which also cooperate in the driving and theguiding of the track.

For the formation of track tread blocks, cores of the character herev involved have..layers of rubber bonded to opposite faces thereof, and the general object of the present invention is the provision of a core which is of such strong and sturdy construction as to enable the tread block of which it forms .a part to,withstand'the. severe abuse to which it .is subjected inusein endless tracks, particularly in the endless tracks of heavy armored tanks and the like.

. A more specific object of the present invention is the provision of tread block cores whichare made of simple and inexpensive sheet metal parts, portions of which are constructed to provide cylindrical passageways through thetread .blocks for the reception of the aforesaid cross rods, and which sheet metal cores, although of relatively lightweight, have surprisingly great strength, rigidity and rug8edness for the efiective re-enforcement of the layers of rubber which are bonded to their opposite faces.

Another more specific object of the present inventionis the provision of a sheet metalcore for a-Ttread block of the type which extends completely across the track in which it is used, said core having simple and inexpensive sheet metal reenforcing members so constructed and ,ar-

ranged as to materially add to the strength, ri 50 gidity and ruggednessofthe core as a whole.

Another more specific object of the present in vention is the provision of a ,tread block core having (a) a pair of, interior sheet'metal members shaped to provide the core with transverse transversely and generally cylindrical passageways adjacent its front and rear edges; (b) :a pair of exterior sheet metal members, one associated with each interior core member, and having portions thereof in contact with and other portions thereof spaced from its associated interior core member; and (0) sheet metalreenforcing members of channel form arranged in the spaces between said interior and exterior core members. said reenforcingmembers lying between and being enerally parallel with the front and rear passagewaysformed by the interior core members.

Further objects of the present invention, and its practical .advantageswill be referred to in or will be evident from thefol-lowing descriptionof a tread block core embodying the invention,- said core beingillustrated in the accompanying draw ing, in which g 1 is a top plan 'viewof the-tread block core here illustrated for' the disclosure of the present inventiomsaid' core being of thetype for usein a. tread block extending. completely across the trackin which itis used, the ;front and rear edges of the layers of rubber which are bonded to opposite faces of said core to formsuchtread block being indicated in dot-dash 7 lines. 2

Fig. 2 is a front elevational-viewtoi-such core, with portions broken away to show inside cone struction, the .outer peripheries of thelayersof rubber which are bonded to opposite faces of the confer the formation of a tread'block being indicated in dot-dash lines; l

Fig. is a view of a tread block containingthe core of Figs. 1 andZ the-view' being partly in vertical section and partly inside elevation on thellne33ofFig.1;

Fig. 4 is a fragmentary perspective viewof one of the channel-shaped sheet I metal re-eni'orcing membersof the core; and

Fig. 5 is a, top plan view of, end portions of two "adjacent tread blocks containing cores of the character here involVedQthe tread blocks 'beinginendless track relationship but with the projecting end portionsof their cross rods unconnected. I

Before" the herein illustrated tread block core is specifically described, "it isto "be understood that the inventionhere involved is not limited to the structural details or, the arrangement of parts here illustrated or described, astreadblock cores embodying the j invention "obviously may take other forms. I It also is, to be understood that the phraseoloey' or. terminology herei em ployed (is for purposes or description and not of therefore interchangeable.

limitation, the scope of the present invention being denoted by the appended claims.

tion relative to the blocks of the neighboring.

row or rows, the present improved cores are particularly suitable for use in tread blocks of the type which extend completely across the track in which they are used, thecores havingsuflimay be provided with rubber linings or the like or the intermediate portions of the cross rods provided with rubber coverings or the like, although obviously, said passageways may be made of such size as to just receivesaid cross rods, as

will be readily understood.

As here shown, welding is used to unite the .two interior core members l8 and IS in superposed relation, the character of the welding and the location of the welded areas being such as to securely and effectively unite said members.

cient strength, rigidity and ruggedness for use in such transversely disposed tread blocks.

Merely for purposes of illustration, therefore,

thecore here shown is for use. in a tread block] A of full track width, and as" the core extends completely across the block, it also is of full track width. To form an endless track from such blocks, a, series of these blocks are connected at the sides of the track in an endless row, as indicated in Fig. 5, the projecting end portions of the transversely disposed front cross rod in of each block A being connected by means not here shown to the projecting end portions of the transversely disposed rear cross rod ll of the preceding tread block A, as will be readily understood. i

Preferably, these interior core members are welded toeach'other along their overlapping front and. rear edge flanges 22 and along their overlapping middle portions between and adjacent the corrugations 20. For the connection by welding of the two interior core members, the front and rear edge flanges of each such member are here provided with transversely spaced welding projections 24, and themiddle portion of each such core member is provided with two rows of transversely spaced welding projections 25, one

row alongside each of the corrugations 20. I'he welding projections 24' and'25 of each interior core member extend in the direction opposite to that of the corrugations 20, and when the two interior core members are first assembled in su-' As best shown in Fig. 3, each tread block A is layers of rubber l3 and Hi, the outer or groundengaging layerof rubber l4 usuallyhaving a somewhat greater thickness than that of the inner layer of rubber l3, as here shown. The core '0f each block is thus sandwiched between two layers of rubber, the core and the rubber layers being coextensive in width as well as in length. As will bef'evident from the accompanying drawing, particularly from Figs. 1 to 3 thereof, the present improved core includes four simple and inexpensive: sheet metal members of generally rectangular form in plan view, These four core members may, and here do, have the same width and length, and they are assembled in stacked relationship, one above another, in a unitary structure, with their peripheries in alignment, as clearly shown in Figs. 2 and 3. Inasmuch as this assembled set of core members has the same length and the same width as the two layers of rubber l3 and M which are bonded to the inner and outer faces thereof, the layers of rubber are efiectively-re-enforced throughout their entire area. For manufacturing economy and simplicity. of assembly, the two exterior core members It and I? are preferably identical and Similarly, the two interior core members 18 and l9'are preferably identical and thus interchangeable, although it is to be understood that these members of the core may differ, if desired, one from another.

As-bestshown in Figs. 1 and 3, each-of the two interiorcore members I8 and i9 is provided adjacent each of its front and rear edge flanges with a transversely disposed semi-cylindrical. corrugation 20. As a result, when the two interior core members are assembled in superposed relation, with their corrugations oppositely disposed and matching, two transverse passageways 2| of cylindrical form are provided, one for the reception of afront cross rod l0 and the'other for the reception of I a rear cross rodil. If desired, the diameter of the core passageways 2| thus formed may be somewhat greater than that of the cross rods l0 and H in order that such passageways perposed relationship, they are of course spaced apart by these welding projections. I i

In order to'space the'welding projections of one interior core member from the corresponding welding projections of the other, inasmuch as the I two interior core members here shown are of duplicate form, and to properly distribute the welded areas, each such interior coremember has its two sets' of welding projections 24 suitably staggered, with acorresponding staggering of its two sets of welding projections 25. 'As here shown,each interiorcore' member has one of its edge flanges provided with a row of six welding projections 24 and its other edge flange provided with a row of seven welding projections 24. As to itswelding'projections 25, each of the interior core members is here shown as having three such projections in each of its two rows thereof.

The two interior core members are so assembled that unlike edge flanges-are brought together, the six'projectio'n flange of one member lying opposite the seven projection flange of the other. The transverse spacing of the welding projections 24 and 25 of each interior coremember is such that when these two core members are thus assembled, there is a row of thirteen transversely spaced welding projections 24 between each pair of contacting edge flanges and two rows of six transversely spaced welding projections' 25 between the contacting middle portions of these core members.

The type of welding preferably used for the uniting of these interior core members is the well known resistance, welding, the welding projections 24 and 25 being melted in the welding operation by the heat caused by the resistance of the electric current. 'Thetwo interior core mem bers are thus united in a particularly effective and durable manner.

Asindicated in Fig. l, the welding projections 24 and 25 not only are spaced entirely across the interior core members l8 and 19 but are located as closely as possible to 'the'corrugations 2 0,the effect of which isto minin iize any, tendency of these two core'members to separate "or become disconnected even under severe conditions ofuse.

two side (or end) edges, by-m'eansoftwo such welding projections 26, as clearly sh'ownin Fig. 1.

As best shown inFig. 3, thestwofexte'rior core members l8 and I! (the top andbottom core members, as they appear in this view)" also are provided adjacent their front and rear edge flanges with transversely disposed corrugations of semi-cylindrical form, the corrugations 2l-of such exterior core members fitting'over the corresponding corrugations -28 of the two interior core members when the extenior'='core members are assembled therewith on opposite faces thereof. For strengthening and therefore re-enforcing purposes, each of the two exterior core mem bers (such members vbeingot'duplicate form, as heretofore pointed out) is provided between its two transverselcorrugations 21 with a centrally disposed rib 28 of generally channel-'shapedxcross section. As shown in Figsnia'nd 3, the ends of the rib 28 of each exterior core member merge with the side walls-oi the corrugations 21 thereof, the top wall 28 of suchrib (exceptior channels therein if they are used) being substantially flush with the tops of such corrugations. Asaresult of this bridging of the two transverse corruga tions 21 of each of the exterior core members, the layers of rubber i3 and H are effectively re-enforced between "the core corrugations; If desired, thetop wall 29 of each or the-ribs 28 may be provided with one or more-channels extending from one corrugation 21 to the other, there being two such channels 38. transversely spacedlin :the top here utilized, and' for that -purpose,]th'e front and rear edge flanges 32 of the exterior core members, andthe fiat side (or end) edge portions 8t'th'ere or, are provided with welding projections iks here shown, there are-twelve welding projections 33 spaced in a row along each of the edge flanges '32 ofeach exterior core memberand a single welding projection 34 in 'each of its side (orend) berson opposite faces thereof. As will be evident from Fig. 1, each edge flange 32 has'it's welding projections staggered with respect to the'welding projections 24 thereof, with the row of weld 'ing projections 33 of eachflange disposed between the row' of welding projections 24 thereof and the free edge of the flange; It also 'will' be evident from Fig. 1 that the welding projections 34, in the side (or end) edge'portions 3| arestaggered with respect to the welding projections 26 of the in:- terior core members, each welding projection '34 beingihere disposed between two'weldingt pro.-

jections26.- l H To increase their strength,rigidity and rugged.-

ness, cores embodying'the present invention inwall of each rib 28, as here shown. 'Ihesechan nels 30 in the ribs 281 1101; only strengthen the exterior core members, 'and'thus the core as a whole, but also aid in the bonding of the layers exterior core members l8 and i1 :areeach provided, on opposites'ides of itsrib-128 andbetween its transverse corrugations 21, witniiatside (or end) edge portions :SLwhich contact/the middle portions of the interior coremembers' 18 and is adjacent their side (or :end) ,edges when. the exterior and interior core members are assembled in superposed or stacked relationship; As aresult of the provision of the,ribs 28;the. coreisoi box like section and hence, is of: exceptionally strong and rugged character.iifTheprovision of the ribs 28 of the exterior core members-also. is of. material assistance in thetransverse anchoring of the layers of rubber"! 3 landfill, inasmuch as the side (or end) portions of said layers extend around such ribs, as indicated by Fig. 2. As the layers of rubber. also extend around the core corrugations to the front and rear core flanges, an efiective anchoring of such layers in a front and rear direction similarly is achieved. To bond or bring about a secure adherence of the layers of rubber to the innerand outer faces of the core, any suitable means may be utilized, such as the copper plating of the exposed faces of the exterior core members, for example.

Inasmuch as the exterior core members [6 and I1 are of duplicate form, no special care need be exercised in assembling them with the two interior core members l8 and IS, on opposite faces thereof. To secure the exterior core members to the interior core members, resistance weldin is elude; in addition to the generally: rectangular interior and exteriorcore members heretofore described, special re-enforcing members whichare,

of course,'of material advantage'in coreswhich are of full back width, such as the core here illustrated. i l I As will be evident from the accompanying drawing, there are two such-special. re-enforcing members in the present core, said members being in the form of sheet metal channels "38 .;(see"-'1. lgs. 3 and 4) having outturned flanges 39. at theif'ree. ;longitudinal edges of their sidewalls 48. "1Eormanufacturing economy and simplicity of assembly, vt ese channel-shaped .re-cnforcing members may be, and. here are, of duplicatecharacter.1

Asbest shown in Fig. 3,- one of these're-enfoming channels 38 is arranged between each interior core memberand its associated oradlacent -exterior core member. More 'specifical1y,-,there' i'sa.

re-enforcing channel between the middle'vportion of each interior core member and'the rib 280i 7 the associated exterior core member, the ,two

channels lying within the ribs .28, insubstantially parallel relation with the core corr'ugationspwith the channel bases 4! in contact with the middle portions of. the interior coremembers and the. channel flanges 39. in

contact, with the top-walls 29 oftheribs. i I

To receive the transversely spaced channels-'38 in the .topwalls 29 of the ribs 28 of theexterior core members I6 and i1, the outturned flanges .39 i

the channel-shaped re-enforcing members has. two setsof transversely spaced depressions 43 in its flanges and side walls. As here shown (see Figs. 1 and 2), the channel-shaped re-enforcing f members 38 are of such length as to more or less snugly fit within the ribs 28 of the exterior core members, but inasmuch as said re-enforcing said re-enforcing members would not occur even if their length were reduced.

As heretofore pointed out, the exposed faces of the two'exterior core members may be copper plated to enable the rubber layers l3 and I4 to be bonded thereto, the layer of rubber l3 being bonded to the exposed face of the exterior core member i8 and the thicker, ground-engaging layer of rubber being bonded to the exposed face of the exterior core member H. In the copper plating of said core faces, which takes place after the core is formed, the use of several solutions is necessary, and in order to avoid any liability of the commingling of such solutions, by the travel of the core from one solution to the next, the present core is provided with both drainage aper: tures and drainage passageways. I

As here shown, each of the corrugations 20 of each of the interior core members is provided with three transversely spaced apertures 45 for the drainage of the channel-shaped ribs 28 of the exterior core members l6 and I1. Drainage passageways 46 also are provided across the bases ll of the channel-shaped re-enforcing members 38, said passageways being transversely spaced and being here shown as in alignment with the drainage apertures 45. As will be readily under stood, these passageways 46 establish communif cation between those portions of the hollow of each rib lying on opposite sides of the channelshaped re-enforcing'member therein, so that the hollows of the ribs are quickly and completely drained.

To those skilled in the art to which the present invention relates, further features and advantages of tread block cores embodying such invention will be evident from the foregoing description of one such core. 1 The present application is a division of application Serial No. 426,666, filed January 14, 1942,

jointly by us and Rudolph I. Schonitzer. Inasmuch as such application Serial No, 426,666 conof such track have cross rods extending there ing a passageway betweensaidt inner core members for a track cross rod, a pair-of outer sheet metal core members rigidly connected with said inner core members and disposed on opposite faces thereof, portions ofsaid outer core members being spaced from opposedportions of said inner core members, and a pair of sheet metal core members engaging saidinner coremembers and said outer core members and located in the spaces between the aforesaid portions thereof 2. A core for the rubber tread block of an'endless track of the type in which the tread blocks of such track have cross rods'yextending' therethrough, said core comprising a pair of inner sheet metal core members rigidly, connected in stacked relation and provided in the region-of each of the front and rear'edges' thereof with a pair of oppositely extending matching corrugations coextensive with the: length of such edges,

each pair of such matching corrugations providing a passageway between said inner core mem-' bers for a track cross rod, a pair of outer, sheet metal core members rigidly connected with said inner core members and disposed on opposite faces thereof; portions of said outer core members being spaced from opposed portions of said inner core members, and a pair ofchannel shaped sheet metal core members, engaging said inner core members and said outer. coremembers and located in the spaces between the aforesaid portions thereof.

3. A core for the rubber tread block of'an endless track of the type in which thetread blocks through, said core comprising a pair of inner sheet metal core members rigidly connected in stacked relation and provided in the region-of each of the front and rear edges thereof with a pair of oppositely extending matching'corrugations coextensive with the length of such edges, each pair of such matching corrugations provid ing a passageway between said inner core members for a track cross rod, a pair of outer sheet metal core members rigidly connected with said inner core members and disposed on opposite faces thereof, portions of saidinner'core members between the pair of corrugations thereof being spaced from opposed and channeled portions of said outer core members, and a pair of channel shaped sheet metal-core members engaging said inner core members and said outer core memthrough, said core comprising a pair of inner sheet metal core members rigidly connected in stacked relation and provided in the region of each of the front and rear edges thereof with a pair of oppositely extending matching corrugations coextensive with the length of such edges, each pair of such matching corrugations provid tions of said outer core 

